The neuroscience community is accumulating a vast amount of human brain mapping data using a variety of techniques that operate over a wide range of spatial scales. Currently its use is generally limited to the laboratory of origin; the data are not readily available to other investigators for subsequent studies. The overall goal of this research is to design, prototype, and evaluate an information infrastructure for human brain mapping data, which will help realize the full potential of this growing store of mapping data. In this initial undertaking, we focus on a system that enables the analysis, exploration, and dissemination of structural Magnetic Resonance Imaging (MRI) data. Our major aims are: 1) to develop and deploy an operational digital library for structural MRI data that will enable users to contribute and retrieve data, as well as explore and analyze associated metadata; 2) to design a data warehouse of structural MRI data that will allow users to manipulate images, explore spatial relationships among regions, and reason about abstract attributes of structural regions (e.g., volume); 3) to design a content-based retrieval system that will allow users to retrieve images with features similar to those in a submitted example; 4) to develop techniques that enable users to dynamically aggregate warehouse information into a probabilistic brain atlas for specified populations of interest; and 5) to develop a prototype system that will ground architecture and query language development in a real world setting so that tradeoffs in design choices may be accurately evaluated.